This study proposes to obtain pilot data on the effects of chronic and alcohol consumption on benzodiazepine receptor (BZR) distribution and density in adolescent onset alcohol dependence using [11C] flumazenil binding visualized by PET. Alterations in the gamma-aminobutyric acid (GABA) neurotransmitter system induced by chronic alcohol consumption represent the mostly likely neurochemical substrate of alcohol dependence. Subjects with adolescent-onset alcohol use disorders, compared with controls, will show reduced binding of [11C]-flumazenil in the cingulate cortex.